Investigating the effect of single-walled carbon nanotubes chirality on the electrokinetics transport of water and ions: A molecular dynamics study

Abstract

The effect of carbon nanotubes (CNTs) chirality on the water electrokinetics transport through CNTs while embedded in silicon nanochannels is studied using molecular dynamics simulation. Voltage difference across the CNTs changed from 0 V to 3.2 V that resulted in a shift in water transport rate from ~8 to ~140 H2O/ns, 4 to ~120 H2O/ns, 15 to ~300 H2O/ns and 10 to ~285 H2O/ns for CNT (8,8), CNT (14,0), CNT (16,16) and CNT (28,0), respectively. In comparison to zigzag CNTs, armchair CNTs showed higher flux for all kind of cations (Na+, K+, Zn2+). It has been shown that water flux through CNTs are not linearly dependent on electric field, yet it faces a peak. Interestingly, zigzag CNTs showed a tendency to retard this maximum voltage to higher values of electric field than armchair CNTs. This work highlights the importance of CNTs chirality effect in future CNT-nanofluidic systems design.